Genetic parameters for quail body weights using a random regression model

A model including fixed and random linear regressions is described for analyzing body weights at different ages. In this study, (co)variance components, heritabilities for quail weekly weights and genetic correlations among these weights were estimated using a random regression model by DFREML under DXMRR option. Data of 1046 pedigreed quail were used. Individual live weights were obtained weekly from hatching to six weeks of age. Records for the same bird were taken as repeated measurements and single measurement error variance was assumed to be constant for all ages. Orthogonal polynomial regressions (on the Legendre scale) of sixth order were sufficient to model the additive genetic, phenotypic and permanent environmental (co)variances. Heritability estimates for ages were moderate, ranging from 0.007-0.61 and estimated measurement error variance was 9.60 g2. Correlations were found positive among weights. Genetic correlations were higher than phenotypic and permanent environmental correlations. The correlations between adjacent periods are more closely correlated than between remote periods. South African Journal of Animal Science Vol.34(2) 2004: 104-10

Sigmoid model for the evaluation of growth and production curves in laying hens

WOS: 000181722300010The aim of this study was to choose the best predictive model for the accurate description of the average flock growth of laying hens and for the daily egg mass being produced by the layers during the productive period. The calculations were undertaken with the generalised data on the weight growth and daily egg mass, produced by the commercial flock of a Shaver White laying hens breed. The model, represented as the ratio of the polynomials of the third and the second powers, was deduced by the authors for the prediction of the growth and daily egg mass production curves. This Narushin-Takma model was tested for the accuracy of the results prediction in comparison with the following growth models: the logistic, the Gompertz, the von Bertalanffy, the Richards, the Weibull and the Morgan-Mercer-Flodin functions. The egg production model used for comparison were the Adams-Bell, the logistic-curvilinear, the compartmental and the Lokhorst functions. Fitting criteria were estimated as the coefficients of determination R-2 and the final loss L-f of the loss function: sum of observed minus predicted data in the second power. The Narushin-Takma model was found to be the best in description of the both curves, values for R-2 of 0.9997 and for L-f of 0.005 for the evaluation of the body growth data and values for R-2 of 0.996 and L-f of 0.001 for the description of the egg mass producing function. The accuracy of the other models was high and almost the same for all functions. The order of the accuracy for the compared models was as follows: for the body growth curve - the Weibull model, the Gompertz, the von Bertalanffy, the Morgan-Mercer-Flodin, the logistic and the Richards functions; for the egg mass producing curve - the logistic-curvilinear model, the compartmental, the Lokhorst and the Adams - Bell functions. (C) 2003 Silsoe Research Institute. All rights reserved Published by Elsevier Science Ltd

Canonical correlation analysis for studying the relationship between egg production traits and body weight, egg weight and age at sexual maturity in layers

WOS: 000228627700004In this study, canonical correlation analysis was applied to layer data to estimate the relationships of egg production with age at sexual maturity, body weight and egg weight. For this purpose, it was designed to evaluate the relationship between two sets of variables of laying hens: egg numbers at three different periods as the first set of variables (Y) and age at sexual maturity, body weight, egg weight as the second set of variables (X) by using canonical correlation analysis. Estimated canonical correlations between the first and the second pair of canonical variates were significant (P < 0.01). Canonical weights and loadings from canonical correlation analysis indicated that age at sexual maturity had the largest contribution as compared with body weight and egg weight to variation of the number of egg productions at three different periods

Heterogeneity of Residual Variances of Test Day Milk Yields Estimated by Random Regression Model in Turkish Holsteins

WOS: 000265888900033Heterogeneity of the residual variances was investigated for test day milk yields of Turkish Holsteins. A third order random regression model including the fixed, random additive genetic, permanent environmental and residual effects were used. Residual Variances (RV) of test day milk yields divided into different classes with 5 schemes as RV1, RV3, RV5, RV7 and RV10. Also, a structural model was fitted to residual variances of milk yields. The residual variances were estimated from 2.19-29.47 kg(2) and additive genetic variances were estimated 3.19-10.97 kg(2). The heritability estimates ranged from 0.12-0.81. The third order random regression models with RV7 and RV 10 schemes were found to be better than others for evaluation of residual variances

Variance components and genetic parameter estimates using random regression models on test day milk yields of Holstein Friesians [Siyah Alacalarda Şansa Bagli{dotless} Regresyon Modelleri Kullani{dotless}larak Denetim Günü Süt Veriminin Varyans Bileşenleri ve Genetik Parametrelerinin Tahminlenmesi]

Genetic parameters for test day milk yields of Holstein Friesian cows were estimated by random regression with Legendre polynomials. The analyzes were applied to 5918 first lactation test day milk yields of 612 Holstein Friesian cows calving from 1987 to 1993 in Dalaman, Tahirova, Sarimsakli and Türkgeldi State Farms. Estimated genetic variances for test day milk yields were larger at extremes of the lactation. Permanent environmental variances mostly decreased in middle part of the lactation. The heritability values for test day milk yields were from 0.26 to 0.57. The genetic correlations between test day milk yields (TD1-TD9) with the last test day milk yield (TD10) were changed from -0.10 to 0.96 and it was high between consecutive test day milk yields, but decreased when the intervals between the test days increased. In random regression models it can be concluded that higher order polynomials were recommended for a sufficient fit of the (co)variance structures over the lactation but a reduction of the orders can also be used for computational simplicity due to small numbers of parameters

Genetic parameters for quail body weights using a random regression model

WOS: 000224120900006A model including fixed and random linear regressions is described for analyzing body weights at different ages. In this study, (co)variance components, heritabilities for quail weekly weights and genetic correlations among these weights were estimated using a random regression model by DFREML under DXMRR option. Data of 1046 pedigreed quail were used. Individual live weights were obtained weekly from hatching to six weeks of age. Records for the same bird were taken as repeated measurements and single measurement error variance (alpha(e)(2)) was assumed to be constant for all ages. Orthogonal polynomial regressions (on the Legendre scale) of sixth order were sufficient to model the additive genetic (alpha(a)(2)), phenotypic (alpha(p)(2)) and permanent environmental (alpha(pe)(2)) (co)variances. Heritability estimates for ages were moderate, ranging from 0.007-0.61 and estimated measurement error variance was 9.60 g(2). Correlations were found positive among weights. Genetic correlations were higher than phenotypic and permanent environmental correlations. The correlations between adjacent periods are more closely cot-related than between remote periods

Effects of an Essential Oil Mixture Added to Drinking Water for Temperature-Stressed Broilers: Performance, Meat Quality, and Thiobarbituric Acid-Reactive Substances

TEKCE, EMRE/0000-0002-6690-725XWOS: 000529366700008This study investigated the effects of an essential oil mixture (EOM; Eucalyptus globulus labill, Tymus vulgaris, Cymbopogon nardus, and Syzgium aromaticum) added to drinking water on temperature-stressed broilers. the performance parameters (body weight, average daily weight, feed intake, and feed conversion ratio), meat quality, and thiobarbituric acid-reactive substances (TBARS) were evaluated. in a 42-d study, 400 Ross-308 male chickens (1-d-old) were randomly assigned to 8 different groups (n = 50), each containing 4 subgroups (n = 8) (22.C Control (C), C + 250 mL/1,000 L, C + 500 mL/1,000 L, C + 750 mL/1,000 L), 36. C (stress control (SC), SC + 250 mL/1,000 L, SC + 500 mL/1,000 L, SC + 750 mL/1,000 L). Adding 750 mL/1,000 L at 22 degrees C and 250 mL/1,000 L at 36 degrees C was more beneficial to the fattening performance parameters than those in the control group. EOM reduced liver weight but increased abdominal fat in the SEOM-250 groups but did not affect other organ weights. EOM had no effect on the TBARS or the b* color parameter while it augmented the a* and L* coordinates of meat color.scientific research projects commission of Bayburt University, Bayburt, Turkey [2017/02-69001-01]This study was funded and supported by the scientific research projects commission of Bayburt University, Bayburt, Turkey (Project code: 2017/02-69001-01). This study was approved by the ethics committee of Ataturk University Veterinary Faculty (22.02.2018/2/24)